This paper provides an overview of the current knowledge of Atlantic forcing of the North Sea's hydro- and biogeochemical dynamics. The North Atlantic Oscillation (NAO) causes the largest short-term variations via common large scale atmospheric variations and the wind-driven exchange of water masses. On longer time scales the zonal shifts in the position of the subpolar front (SPF) in the eastern North Atlantic, also triggered by the NAO, determine the oceanic settings in the northern and central North Sea. The hydrodynamics of the southern North Sea are influenced more by local forcings. The influence of Atlantic forcing extends to the biogeochemistry of the northern North Sea, but its influence on primary production is still unclear. Climate change is expected to reinforce some of the forcing mechanisms but may reduce others, and further work is advised to firm up the projections available to date.